Zeolites, which are typical porous materials, are aluminosilicates wherein a silicate skeleton has developed three-dimensionally. Zeolites have molecular-size pores and a stereoselective adsorptive action, so that they have a function as molecular sieves. In addition to tens of naturally occurring zeolites, many kinds of zeolites have been synthesized hitherto and are extensively used in the fields of catalysts, separative adsorbents, ion exchangers, and the like.
Aluminophosphates, AlPO.sub.4, which are like zeolites and are anhydrous neutral salts in that they do not contain silica, can have an isoelectronic structure similar to that of silica. Thus, like zeolites wherein a silicate skeleton has developed three-dimensionally, aluminophosphates can have a skeleton structure of [AlO.sub.4 ] tetrahedral structures and [PO.sub.4 ] tetrahedral structures arranged alternately. S. T. Wilson et al. have reported that hydrothermal reactions, in which a variety of amines have been added as organic templates, can selectively produce aluminosilicate molecular sieves having more than 10 different skeleton structures (U.S. Pat. No. 4,310,440; 1982). These aluminophosphates have micropores of effective pore diameter 0.3 to 1.0 nm, and they are useful as adsorbents and porous carriers used to support catalysts. Besides these, many similar aluminophosphates having micropores have been reported.
Further, there are reports of compounds (SAPO) in which part of aluminum atoms have been substituted by silicon atoms in an isomorphous manner (U.S. Pat. No. 4,440,871; 1984), as well as many useful AlPO substitution products (U.S. Pat. No. 4,554,143; 1985), in which isomorphous substitution with transition metals and the like has been made, and they are shown to be used as ion exchanges, catalysts, and the like.
Since, in these molecular sieves, however, the inner wall of the pores is composed of oxygen atoms, generally many of the molecular sieves are hydrophilic and the pore structure is poor in flexibility. These properties narrow the range of the use of these molecular sieves as separating/adsorbing materials for nonpolar organic materials. The size and shape of the pores of these conventional molecular sieves are all determined by the skeleton of the inorganic oxide. Although the size and shape of the pores can be controlled roughly, it is difficult to control the shape of the pores precisely.